Introduction . Since the discovery of hydrogen sulfide (H 2 S) as a nitric oxide (NO)-like signaling molecule in recent years, research on H 2 S and its related reactive sulfur species has exploded1 , 2 , 3. A hot topic in this field is to develop compounds or materials that can precisely control the release of H 2 S or its related sulfur species and to explore their applications4 , 5 , 6 , 7 , 8. In this regard, hydrogen persulfide (H 2 S 2 ), a highly ...